Global nuclear generation capacity increased by 4.2 gigawatts (GW), or 1.1 percent, to 373.1 GW and the number of operational reactors also increased by two units to a total of 437 nuclear reactors worldwide last year. The increases are net figures, taking into account new plants, decommissioned reactors, and units returned to service after having been offline for a certain period.

Expansion of nuclear power generating capacity has slowed considerably—just 75 GW were added, compared with 296 GW during the preceding quarter century. Today, nuclear power is the only mainstream energy technology that does not show significant growth. Its share of the world’s primary energy supply actually fell, from 6.4 percent in 2002 to just 4.5 percent ten years later.

Although nuclear power is dispersed widely across the globe, it is most heavily used in industrialized countries. Of the 10 nations with the highest nuclear power production, 9 are industrialized countries, with China being the other one. China has led the world in capacity additions in recent years, and its 3.1 GW of new capacity accounted for 45 percent of global starts in 2012.

With 102.1 GW capacity and 104 reactors, the United States remains the world’s leading producer of nuclear power. In France, however, the share of nuclear in overall power production is higher—its 58 reactors contribute 75 percent of the country’s electricity supply, compared with 19 percent in the United States.

Worldwide, construction began on seven new reactors during 2012, with total planned capacity of 6.9 GW, well short of the 15.8 GW of capacity that went online in 2010, when start-ups surged. Worldwide, some 67 nuclear reactors with a total capacity of 64.3 GW are currently being built. However, 7 of these have now been under construction for more than 20 years, suggesting that their completion is doubtful.

Three key factors account for the stagnancy of nuclear power. The first and most important one is that nuclear energy is not cost competitive with fossil fuels and renewable energy sources. It is just too expensive. Second are safety concerns. After the many accidents we have had over the years—with Chernobyl, Fukushima, and Three Mile Island just a few examples of some of the worst incidents; problems occur on a regular basis. And despite stricter oversight in some countries, public opposition to nuclear energy is high almost everywhere in the world. Finally, the storage of nuclear waste still remains unsolved. Nobody really knows what to do with itand nobody wants to have the hazardous material sit in their backyard.

Apart from the ongoing ecological catastrophe around Fukushima, water leaks in France and Taiwan and radiation leaks in the United States have contributed to public nervousness about the technology. In August 2012, evidence of a leak was found in one of the 177 underground double-shell waste tanks at the Hanford Nuclear Site in the United States—tanks that were thought to be stable and impervious. To date, no solution to the nuclear waste challenge has proved safe and reliable for the extremely long time spans needed for nuclear radiation to abate.

Further highlights from the report:

Europe is the most reactor-saturated continent, with 170 plants—some 39 percent of the global total.

In Asia, China anticipates continued growth in its nuclear sector; it has 17 plants in operation, 29 under construction, and 38 in the planning phase.

French president Francois Hollande recently declared his intention to reduce the reliance on nuclear power from 75 percent of electricity generation to 50 percent by 2025, with continued nuclear phaseouts in Germany and Switzerland.

Prior to the 2011 earthquake and tsunami, Japan generated 30 percent of its electricity from nuclear power—a share that was expected to increase to 40 percent by 2017; instead, all reactors are currently offline.